Turbine engines, and particularly gas or combustion turbine engines, are rotary engines that extract energy from a flow of combusted gases passing through the engine onto a multitude of rotating turbine blades. Typically a fan section is utilized to take in ambient air and direct it to different components of the engine for extracting energy and cooling purposes. Some of the fan air is initially directed into the compressor stages, while other portions of the fan air continue through outlet guide vanes and can later be directed into the engine components as needed.
Gas turbine engines include offtakes in areas of the engine where air is extracted from high-velocity, swirling channels to the internal air system for cooling, sealing or heat management purposes. When the angle of redirection is 90° or higher louvers or other aerodynamic shapes are required to turn the flow effectively. The louvers are typically cascades of equal length, shape and camber angle.